In today's aircraft cabins, panels of overhead passenger service units (PSUs), supporting components such as reading lights, oxygen masks, gaspers, loudspeakers, optical signs and switches, are most often mounted to a mounting rail preferably made of aluminum that keeps the panels from moving in most directions. However, when just hanging down from the mounting rail during installation, these panels are supposed to slide along the longitudinal direction of the mounting rail to allow for tolerance adjustment and pushing them in the right location. Once the final position is found, a stopper element (“x-stopper”) is installed into a cut-out of a PSU to take the x-loads of the PSU weight in case of a crash, with x-loads referring to loads in the longitudinal direction of the aircraft. In a typical aircraft cabin, more than 120 x-stoppers need to be manually placed and tightened. This is a fairly tedious job, which costs time and money on the final assembly line. Also, the x-stoppers add considerable weight to the aircraft. Once tightened, there is no flexibility for a fast rearrangement of the PSUs. Thus, it is nearly impossible to change the layout of the aircraft cabin over night. Furthermore, non fastened stopper elements are not readily visible, as they are covered by the PSUs, and thus provide a considerable risk for hidden failures.
It therefore would be beneficial to provide an improved fastening structure for fastening overhead passenger service units at the aircraft support structure.